In session: President George W. Bush is shown speaking at the White House in this May 2007 file photo. During winter recess, Democrats keep Congress in session, a procedural tactic to thwart Bush. By staying in session, the Senate preempts potential recess appointments.

"We had the government shutdown under President Clinton. But the added factor you have now – more so than in the 1990s – is a phenomenal press for presidential power. The Senate won't leave town because there is no more trust that the president will respect the institution of Congress," he adds.

Political analysts say it's too early to tell if this new procedural weapon means that recess appointments are a thing of the past. Mr. Bush has made 165 recess appointments, most recently on Oct. 15, according to the US SenateHistorical Office. During his eight years in office, Mr. Clinton made 140, including 53 between sessions of Congress.

Some 43 federal judicial vacancies are pending, including 13 appeals court vacancies. "Historically, that's not an exceptionally high number. But for some circuits, such as the Fourth Circuit, where all the terror cases have been brought, there are five vacancies out of 15 judges," says Carl Tobias, a law professor at the University of Richmond in Richmond, Va. "It used to be considered the most conservative court in the country. If a new president gets to appoint five of 15 judges, it dramatically shifts the balance on that court."

In addition, four recess appointments at the Federal Election Commission expired last month – leaving the six-member board short of a quorum to operate. Democrats opposed the nomination of one interim appointee, Hans von Spakovsky, citing concerns over his commitment to voting rights for African-Americans. Democratic Sens. Russ Feingold of Wisconsin and Barack Obama of Illinois have put a hold on the nomination, and Senate Republicans say that all four nominees must move together.

"It's not a good moment to have the FEC in limbo, just as the presidential election heats up," says Professor Zelizer. "You don't want to have it further stifled by Congress and the president not being able to function."

But the winter of discontent between Congress and the White House is thawing on at least one point: Aides on both ends of Pennsylvania Avenue expect a quick fix to the fiscal year 2008 defense authorization bill that will allow Bush to sign it.

Last week, the president announced that he intended to veto the bill, citing provisions that would interfere with Iraq's reconstruction efforts.

The Armed Services committees are gearing up to fix the bill early in the new session of Congress. "There is recognition that this is an issue that does need to be fixed. We need to make sure that Iraq has the ability to continue to reconstruct and rebuild," says White House Deputy Press Secretary Scott Stanzel.